Estimating the risk of fatal traffic accidents posed by drivers with epilepsy in Japan: A comparison with traffic accidents caused by sudden death of occupational drivers

Purpose: Proper judgement of the aptitude of people with epilepsy (PWE) for driving is a critical issue, both medically and socially. One thus far reported approach is a quantitative comparison of the risk of fatal traffic accidents caused by PWE drivers and that by subgroups of drivers in the general population. We propose a new approach that compares the risk posed by PWE drivers and that by sud-den death of occupational drivers, and the maximum driving time for PWE based on that comparison. Method: The risk of fatal traffic accidents was estimated using four variables. The value assigned to each variable was determined using reports and statistics. Results: The risk of fatal traffic accidents caused by sudden death of occupational drivers was estimated to be 7.6×10^-5/year, 4.9×10^-5/year, and 1.7×10^-5/year for large-sized, mid-sized and normal-sized vehicles. The risk of fatal traffic accidents caused by PWE drivers was estimated to be 5.3×10^-5/year and 3.2×10^-5/year for PWE with seizure-free periods of 1 year and 2 years, respectively. The maxi-mum acceptable driving time for PWE having a 2-year seizure-free period at the equivalent risk caused by sudden death of occupational drivers of mid-sized vehicles was estimated to be 304 min/week. Conclusion: The risk of fatal traffic accidents caused by PWE drivers can be evaluated by com-paring to that caused by sudden death of occupational drivers. Such risk posed by PWE drivers having a 2-year seizure-free period was less than that caused by sudden death of occupational drivers of mid-sized vehicles. Assuming that the society accepts the latter risk, PWE may be permitted to drive for an estimated maximum time at the equivalent risk of causing a fatal accident.